Changes

<p>In the foetus the spleen also has a role in [[Overview of Haematopoiesis - WikiBlood|haematopoiesis]] when it becomes the main [[Erythrocytes - WikiBlood|erythrocyte]] producing organ during the haematopoietic transitional phase.</p>

<p>In the foetus the spleen also has a role in [[Overview of Haematopoiesis - WikiBlood|haematopoiesis]] when it becomes the main [[Erythrocytes - WikiBlood|erythrocyte]] producing organ during the haematopoietic transitional phase.</p>

<p>In the developed animal the red pulp is involved in the removal of aged, damaged or abnormal [[Erythrocytes - WikiBlood|erythrocytes]] (along with the [[Liver - Anatomy & Physiology|liver]] and [[Bone Marrow - Anatomy & Physiology|bone marrow]]). As [[Erythrocytes - WikiBlood|erythrocytes]] age they become less supple and this causes them to become damaged when they pass through the very narrow capillaries of the spleen, after which they are phagocytised by splenic [[Macrophages - WikiBlood|macrophages]]. If a splenectomy is performed the number of aged [[Erythrocytes - WikiBlood|erythrocytes]] in circulation increases.</p>

<p>In the developed animal the red pulp is involved in the removal of aged, damaged or abnormal [[Erythrocytes - WikiBlood|erythrocytes]] (along with the [[Liver - Anatomy & Physiology|liver]] and [[Bone Marrow - Anatomy & Physiology|bone marrow]]). As [[Erythrocytes - WikiBlood|erythrocytes]] age they become less supple and this causes them to become damaged when they pass through the very narrow capillaries of the spleen, after which they are phagocytised by splenic [[Macrophages - WikiBlood|macrophages]]. If a splenectomy is performed the number of aged [[Erythrocytes - WikiBlood|erythrocytes]] in circulation increases.</p>

<p> The red pulp also acts as a storage site for [[Erythrocytes - WikiBlood|erythrocytes]]. The degree of storage is variable between species but is particularly notable in horses which during exercise under sympathetic activity can contract their spleen to increase the concentration of circulating [[Erythrocytes - WikiBlood|erythrocytes]]. In some species such as cats and rodents the red pulp acts as a storage site for [[Thrombocytes - WikiBlood|platelets]] and contains [[Thrombopoiesis - WikiBlood#Megakaryocyte|megakaryocytes]].</p>

<p> The red pulp also acts as a storage site for [[Erythrocytes - WikiBlood|erythrocytes]]. The degree of storage is variable between species but is particularly notable in horses which, during exercise under sympathetic activity, can contract their spleen to increase the concentration of circulating [[Erythrocytes - WikiBlood|erythrocytes]]. In some species such as cats and rodents the red pulp acts as a storage site for [[Thrombocytes - WikiBlood|platelets]] and contains [[Thrombopoiesis - WikiBlood#Megakaryocyte|megakaryocytes]].</p>

===Lymphoid===

===Lymphoid===